Hewlett-packard Development Company, L.p.

Other

Compaq Computer Corporation, Inc.

Robert S Wright

Nam H Nguyen

Robert C Brooks

Binh T Truong

Michael R Durham

Louis B Hobson

Richard W Clutter

Patrick Lee Ferguson

Bassam N Elkhoury

George Farris Squibb

Russell J Wunderlich

Joseph A Clegg

Kris P Dehnel

Examples herein disclose determining whether a computing device should implement a zero watt state according to an engagement of a button. The examples disconnect a power source to the computing device based upon the determination the computing device should implement the zero watt state.

Determination of a zero watt state for implementation

Examples disclose a computing system comprising a host device with a connection socket to support multiple types of cables by detecting a first key position and a second key position for determination of the type of cable. Further, the computing system comprises a switching circuit to determine a logic state of each of the key positions. Additionally, the switching circuit is to deliver power associated with the type of cable based on the logic states of the key positions.

Detecting key positions to determine a type of cable

One of a first voltage and a second voltage may be selected based on input from a basic input/output system (BIOS). One of the selected voltage and no voltage may be output to a carrier detect (CD) pin and a ring Indicator (RI) pin of a serial communication port, based on the input from the BIOS.

Output voltage to serial communication port

A network powered device includes field effect transistors connected as bridge circuit. The bridge circuit includes control circuitry to enable the FETs based on completion of a powered device detection sequence performed by power sourcing equipment coupled to the device via an Ethernet link.

Bridge circuit for Ethernet powered device

Embodiments herein relate to controlling a connection to an interface. In an embodiment, a protection circuit is to detect a voltage at an input rail of a regulator, where the regulator is to provide power to a peripheral device via an interface. Next, the protection circuit is to compare the detected voltage to a reference voltage. Then, the protection circuit is to generate a detection signal based on the comparison. Lastly, the protection circuit is to disable a connection between the regulator and the interface based on the detection signal.

Interface connection control based on voltage at input rail

A protective circuit compares at least two different signals and asserts a control node toward respective logic states accordingly. At least one of the signals is derived from a voltage on a power rail within a computer or other device. A switching element passes or isolates an enable signal based on the logic state of the control node, enabling or preventing operation of a power supply, accordingly. Central processing units (CPUs) or other elements are protected against electrically caused damage in the event that a fault is detected by the protective circuit.

Protective circuitry controls power supply enablement

A first resistance () within a power supply () can be connected to a power supply output (). A variable resistance () can be serially coupled with the first resistance, thereby providing a first intermediate voltage at a point () disposed between the first resistance and the variable resistance. The variable resistance can be at a maximum in the absence of an expansion device () and at less than maximum in the presence of an expansion device. The first intermediate voltage and a second intermediate voltage () can be introduced to a comparator (). The comparator can provide an output signal () when the first intermediate voltage exceeds the second intermediate voltage. The comparator output signal can be used to confirm the power supply capacity to power an external device () and to enable one or more external device functions.

Variable adapter ID circuit

Apparatus and methods related to limiting surge current are provided. An under-voltage condition on a node is sensed and respective signals are provided in response. The under-voltage condition correlates to a surge in load current drawn from the node. A foldback signal is provided to a power controller to adjust the voltage on the node. The foldback signal is nullified when the surge current condition has been curtailed. Printers, computers and other apparatus can include surge current-limiting accordingly.

Apparatus and methods for limiting surges in load current

A system comprises an AC/DC adapter having a connector. The system also comprises a portable computer that receives said connector. The portable computer comprising a delay circuit coupled to a power transistor that is coupled in parallel with a resistor. The delay circuit causes the power transistor to activate following a time delay after current from the adapter begins to flow through the resistor. As a result of a user beginning to remove the connector from the portable computer, a control transistor is activated to reset the delay circuit.

Delay circuit with reset feature

The present invention relates to a fault tolerant system for providing power to a multiple central processing unit computer system. Three DC-DC converters, each sized for providing power to one central processing unit, furnish power to two central processing units through two power planes. Each DC-DC converter has an output voltage level selectable through a voltage identification signal. If the voltage identification signals of the converters match, identification logic couples the power planes together. If only one converter is available to power the two central processing units, a stopclock logic circuit alternatively places the central processing units in known stopclock modes. Thus, the single converter only has to fully power one central processing unit at any one time.

Redundant CPU power system

A synchronized switch tapped coupled inductor circuit which couples a first closed-loop regulated output of a forward converter switching power supply to a second output to assist in regulating the voltage of the second output. The switched power supply includes a converter transformer which is implemented as a forward converter providing the multiple outputs. The second output includes a storage inductor which is coupled to a storage inductor of the first output. The second coupled inductor includes a center tap which is connected to a synchronized switch. The synchronized switch is further connected to the first output and coupled to the converter transformer to detect the forward and flyback portions of each cycle. During the flyback portion of each cycle, the switch is turned on coupling the center tap to the first output. During the forward portion of each cycle, the switch is turned off, isolating the outputs from each other.

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Spring, TX, United States of America

Robert S Wright